This invention relates to photoelectric controls used to energize lamps in changing ambient light conditions.
There have been many controls designed to energize lamps when ambient light levels drop below a predetermined point. Many lamp controls operate in a dusk-to-dawn mode of operation, for example. The reason most controls operate in this manner is obvious; more light is often needed or desired only when the ambient light has decreased to the point that it is unsuitable for the purpose at hand.
In perhaps no case does a light control energize a lamp as ambient light levels increase. This mode of operation could be useful, however, in certain situations. For example, it would be useful for a lamp to be energized when the door to a closet is opened, exposing the interior of the closet to an increased, but still insufficient, amount of light. It is understood that certain products may fulfill this need by detecting motion. These products are, unfortunately, relatively expensive.
An object of the present invention is to provide a photoelectric control that energizes a lamp when ambient light levels increase. Another object is for the control to respond only to a rapid change from a previous level of ambient light. Another object is to de-energize the lamp after it has been energized for a period of time. Still another object is to energize the lamp each time power is removed and reapplied, regardless of the ambient light level. A final objective is to provide a simple design for the control which will result in a small and inexpensive product which can readily be used in homes and businesses.